Semantic integration declines independently of working memory in aging

Abstract

Semantic integration and working memory both decline with age. However, it remains unclear whether the semantic integration decline is independent of working memory decline or whether it can be solely explained by the latter factor. In this event-related potentials experiment, 43 younger adults and 43 cognitively healthy older adults read semantically congruent and incongruent sentences. After controlling for working memory, behavioral accuracy was significantly lower in the older adults than in the younger adults. In addition, the semantic integration related N400 effect (incongruent vs. congruent) for correct trials was apparent in the whole brain in the younger adults but restricted to the posterior region in the older adults. The results clarify the relationship between working memory and semantic integration, and clearly demonstrate that semantic integration decline is independent of working memory decline during aging.

Sentence comprehension in ageing and Alzheimer's disease

“…Searching through semantic memory for category-appropriate words takes older adults longer, not just because their cognitive abilities are slowed, but because they have a greater volume of semantic memory to search through. The suggestion that semantic access is slowed, but semantic abilities themselves are not impaired, is consistent with the robust finding of greater vocabulary size in older adults (e.g., Hardy et al, 2017;Hartshorne & Germine, 2015;Zhu et al, 2019) and, importantly, with the notion that an absence of semantic content in sentences increases older adults' sentence processing difficulties (Poulisse et al, 2019). The study by Poulisse et al (2019) found stronger age-related declines on agreement error detection measures for pseudoverbs compared to real verbs, suggesting that semantics may act as a type of compensation mechanism for impaired syntax processing.…”

“…The natural interaction between these modules implies that older adults can compensate for impaired syntactic processing by prioritising semantic information. Older adults' greater semantic knowledge and vocabulary size (Hartshorne & Germine, 2015; Zhu et al, 2019) are, in this view, used to balance out WM issues in sentence comprehension. Evidence for this position was found by Poulisse et al (2019), as mentioned earlier, who discovered increased deficits and poorer performance on stimuli with an absence of semantic content (in this case, pseudowords) compared to real words.…”

Effects of Healthy Aging and Gender on the Electrophysiological Correlates of Semantic Sentence Comprehension: The Development of Dutch Normative Data

“…Conversely, no significant effect of aging on the N1 and P2 amplitudes has been found (Gunter et al, 1992;Kutas et al, 1998). Finally, aging effects on the LPC effect elicited during an SSCT have been reported by Zhu et al (2018Zhu et al ( , 2019 and Xu et al (2017). The authors observed a significant LPC effect in elderly participants only.…”

“…At word level, lexical-semantic knowledge (including categorical and associative relations) is retained with increasing age as shown by behavioral (Giffard et al, 2003) and electrophysiological priming studies (Cocquyt et al, 2022). At sentence level, behavioral results are more heterogeneous since both lower (Xu et al, 2017;Zhu et al, 2018Zhu et al, , 2019 and similar (or even higher) accuracy scores (Federmeier et al, 2010;Iragui et al, 1996) in elderly compared to young subjects have been reported. The latter heterogeneity is probably related to between-task differences in the required cognitive resources.…”

“…Electrophysiological studies targeting semantic congruity effects (i.e. the comparison of ERPs elicited during a congruent and incongruent condition) in the visual modality reveal significantly reduced amplitudes (Federmeier et al, 2010;Gunter et al, 1992;Iragui et al, 1996;Kutas & Iragui, 1998;Xu et al, 2017;Zhu et al, 2018) and increased latencies of the N400 effect (Federmeier et al, 2010;Gunter et al, 1992;Iragui et al, 1996;Kutas & Iragui, 1998;Xu et al, 2017;Zhu et al, 2018Zhu et al, , 2019 in older compared to young participants. Gunter et al (1992) showed that these age-related changes were already present in middle-aged subjects (mean age: 56 years), which clearly emphasizes the need to investigate aging effects on language processing across a broad age range.…”